The present invention generally relates to packages for containing one or more batteries, and more particularly relates to a package for containing an air cell or air-assisted cell battery for use with an electrically operated device.
Conventional electrochemical cells such as miniature alkaline air cell and air-assisted cell batteries are commonly employed for supplying a battery voltage in a generally disk or cylindrical-shaped construction. Examples of conventional miniature air cell batteries are disclosed in U.S. Pat. Nos. 5,306,580, 4,404,266, and 5,843,597. Examples of air-assisted cell batteries are disclosed in U.S. Pat. Nos. 5,079,106, 5,229,223, and 5,270,128. Air cell batteries and air-assisted cell batteries are commonly employed in electrically operated devices, such as hearing aids and pagers. The conventional air cell battery has an anode typically containing zinc powder as the active material, and a cathode which employs oxygen received through an air inlet from the surrounding ambient air as the active material. The conventional air-assisted cell battery, generally employs a cathode containing an active electrochemical material such as manganese dioxide or silver oxide and further employs oxygen received through an air inlet from the surrounding atmosphere air to regenerate the catalyst to charge the active material.
Alkaline batteries that require oxygen from the ambient air received through an air inlet are generally packaged and sold with a removable tab, typically made up of an adhesive tape, that covers the air inlet openings formed in the cathode container. The removable tabs prevent atmospheric air from freely entering the cell when the openings are covered, and is removable to allow for atmospheric air to enter the cathode container to allow for electrochemical reaction to occur. Vapor pressure within the cell is generally determined by the electrolyte in the cell which typically comprises a salt solution, such as an aqueous solution of potassium hydroxide. The removable tab serves to prevent excessive moisture from entering the cell as well as to prevent excessive moisture from leaving the cell. Excessive moisture collection in the cell will consume the void volume, thereby leaving reduced volume for reaction product and resulting in premature shutdown of the battery. Excessive migration of moisture from the battery will dry up the cell and result in inefficient discharge. By covering the air inlet openings with a removable tab, air cell and air-assisted cell batteries may be stored for long periods of time prior to use, without suffering from noticeably reduced performance due to excessive or inadequate amounts of moisture in the cell.
It is sometimes desirable to package electrically-operated devices, such as hearing aids, with one or more miniature batteries disposed in the device so that the device is ready to operate. For such devices, it is desirable to provide the battery intact in the device so the device is ready to operate, without requiring a user to remove a tab from the air inlet openings on the battery container. However, by omitting the covering tab, the reactive components of the battery are exposed to the vapor conditions of the surrounding environment. One proposed solution to minimizing the adverse effects of certain vapor conditions is to package the battery and electrically-operated device together in a low-permeability polymeric blister package. However, conventional blister packages are generally vapor permeable, and reduced vapor permeable materials add substantially to the package cost As a consequence of vapor permeation, vapor may enter or leave the package when the vapor pressure within the package is different from the vapor pressure of the surrounding atmosphere, and may thereby adversely affect the performance of the packaged battery. Additionally, carbon dioxide may also permeate the package and react with the electrolyte to adversely affect cell performance.
Accordingly, there is a need, heretofore unfulfilled, to provide a package for housing one or more air cell or air-assisted cell batteries in a manner that does not require a tab covering the air inlet opening(s) of the battery. It is further desirable to provide for a battery package that prevents excessive moisture transfer entering or exiting the cell. It is further desirable to provide for such a package that includes an electrically-operated device containing an air cell or air-assisted cell battery ready to operate.